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Finding the Fourth Proportional to 912.83, 1,257.21 and 788.42

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Solution

The fourth proportional to 912.83, 1,257.21 and 788.42 is: 1,085.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    912.83 : 1,257.21 = 788.42 : x
  2. Step 2: Convert to fraction form
    912.83/1,257.21 = 788.42/x
  3. Step 3: Cross multiply
    912.83x = 1,257.21 × 788.42
  4. Step 4: Simplify right side
    912.83x = 991,212.65
  5. Step 5: Solve for x
    x = 991,212.65/912.83
  6. Step 6: Final answer
    x = 1,085.87

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.